The present invention generally concerns flexible bags, bag arrangements or pouches that include a gas vent or gas filter arrangement. In particular, the invention concerns an arrangement which in operation: can be closed and sealed about an object or objects contained within the bag arrangement; and, from which certain types of gas build-up in the pouch arrangement interior can be readily released, in a preferred manner. Preferred applications concern such arrangements including means for opening and resealing, during use. The invention also concerns methods for preparing such bag arrangements, and methods of use.
A variety of items are marketed enclosed within flexible bags or bag constructions. Among other things, such constructions can generally operate to: protect the enclosed item(s); retain a plurality of items in close association with one another; facilitate storage and handling; facilitate access to a portion of a stored quantity; and/or to inhibit contamination (and maintain freshness) of stored material. A variety of bag designs have been used, for such purposes.
In some instances, items stored within the bag construction are not completely stable, after the construction is sealed closed. For example, at a food processing/packaging plant materials such as coffee beans may be packaged (sealed) within such bag constructions, while hot. As materials such as coffee beans cool, gases are given off. These gases will expand the flexible bag construction taut, and eventually rupture it, unless vented.
To maintain integrity of the bag construction under such circumstances, vented bag arrangements have been developed. A frequently used general type of construction is one which involves an aperture or pore in a side wall of the bag construction, which is covered by a porous filter. As gas pressures build up within the sealed bag arrangement, the gases can pass outwardly through the vented pore and filter, to reestablish equilibrium of pressure between the interior and exterior of the bag. One commercially available filter for such use is the Bosch filter available from Robert Bosch Corporation. This filter arrangement generally comprises a piece of porous polymer material including portions having adhesive thereon, selectively positionable over a pore in the bag.
Conventional vented flexible bag arrangements for containing materials such as coffee have not been completely satisfactory in function. Reasons for this include the following: such constructions have not, in general, been conveniently constructed for ease of opening and resealing; the position of the vent or filter has not been completely desirable for maintenance of integrity during shelf life and use; and, the position of gas vents or filters in such arrangements have not been fully satisfactory with respect to potential interference with the operation thereof by material received within the bag, during use.
A better understanding of conventional arrangements can be obtained from consideration of the conventional arrangement illustrated in FIGS. 1 and 2. In FIG. 1 there is depicted, in perspective, a conventional, vented, flexible bag arrangement 1 having material 2 (such as coffee beans 3) stored therein. Arrangement 1 has first and second closed ends 5 and 6 and opposite sides 7 and 8. End 6 is preferably relatively permanently closed, by staples, adhesive or the like. End 5 is also closed (at the packaging plant) by means such as staples and/or adhesive; however it is opened (by the consumer or user) for access to an interior, to remove coffee 3 therefrom. In use, end 5 is reclosed by rolling that end of the bag up, and clipping, clamping, taping or otherwise securing the rolled up end in a tightly coiled configuration. As arrangement 1 is further depleted of its contents, during further use, end 5 is further rolled and compressed toward end 6. Reasons why this type of closure has been preferred include the fact that to maintain material 2 within arrangement 1 as fresh as reasonably possible, it is generally desirable to leave as little air in the arrangement 1, during storage, as easily manageable.
Still referring to FIG. 1, on an upper surface 10 of arrangement 1 a vent system or arrangement 15 is positioned. Vent arrangement 15 comprises a porous polymer filter arrangement or member 16 positioned over a pore 17. Pore 17 extends through surface 10, into fluid flow communication with an interior 18 of arrangement 1. Gas pressure build-up within arrangement 1, then, is vented by passage of the gases through porous filter member 16. The filter member 16 is selected, however, so that solid particles and the like do not pass there through. Thus, the contents of the bag do not leak outwardly. Also, preferably member 16 is selected so that it acts as a barrier to microorganism and moisture passage into the bag 1, to maintain freshness.
In a typical use, arrangement 1 is constructed with one open end (for example end 5) and is filled with material 2 to be stored, while material 2 is still in a hot state. The open end (end 5 in the example) is then sealed closed, and as the material cools, gases are given off. The gases build up pressure within arrangement 1 and are vented through pore 17 and filter member 16.
When the arrangement is ultimately obtained by a consumer, end 5 is opened, as necessary, for removal of material stored therein. As described above, end 5 is reclosed by collapsing, folding or rolling it toward end 6, and is maintained closed by means such as a retainer, clamp or tape. This practice is repeated, until the contents are completely used.
Typical operation of the arrangement 1 as just described, involves at least two potential problems. First, as end 5 is reopened and reclosed during use by the consumer, eventually the consumer will collapse or roll end 5 past vented arrangement 15. This poses little problem with respect to the required operation of vent arrangement 15, since its purpose will generally have been served prior to the consumer even obtaining the arrangement. However, a potential problem is nevertheless presented. In particular, vent arrangement 15 represents a portion of the overall construction 1 in which, as a result of the pore 17 and the filter member 16, a site of potential failure is presented. For example, in general, conventional arrangements utilized as a filter member 16, are not as flexible as materials used as the side walls, i.e. surface 10, of typical bag constructions 1. If the vent arrangement 15 resists coiling or collapse during the folding/rolling process involving end 5, the vent arrangement 15 or the construction 1 may tear or rupture, leading to a failure in the integrity of a side wall of arrangement 1. Thus, inconvenient spills, etc., may occur. Further, loss of freshness, due to loss of integrity of the closed system, may result. Similar problems would occur if instead of rapture, separation of the filter member 16 from the construction 1 occurred.
Another potential problem is presented from the location of arrangement 15. In particular, its position is such that when arrangement 1 is filled during packaging, solid material is present within arrangement 1, directly adjacent vent arrangement 15. Such solid material may interfere with free flow of gases through the vent arrangement 15. For example, prior to cooling and releasing of gases, small particles (i.e. dust) within the stored material 2 may block pore 17 and/or filter 16, so that when the gases are released from the stored material, they are not as readily vented from the bag arrangement 1.
Another potential problem with the arrangement of FIG. 1 is that it is not especially convenient for the consumer to use, from the point of view of opening and reclosing. For some consumers it may be inconvenient to perform the ritual of rolling the end 5 of arrangement 1, between uses, and finding a method of maintaining same closed, for example, through use of tape or clamps. While some conventional arrangements include wires therein (or tape thereon) to facilitate the process, these may be relatively expensive to provide and/or inconvenient to use. Further, they may represent yet another site of potential failure in the construction or maintenance of closure.
To further facilitate understanding of the arrangement of FIG. 1, attention is directed to FIG. 2. FIG. 2 is a perspective view of a panel 20 having a vent arrangement 21 therein, from which an arrangement such as that of FIG. 1 can be formed. That is, arrangement 1 of FIG. 1 is formed from a single panel, and thus provides for a single seam. Formation of the seam will be understood by reference to FIG. 2, wherein panel 20 is shown folded to form upper surface 25 opposite side gussets 26 and 27, and back panels 28 and 29. In practice, a tube arrangement (with a single longitudinal seam) is formed by joining back panels 28 and 29 to one another. The tube arrangement is then closed along one end, for example end 30, prior to filling with material. After filling with material, the opposite end 31 is then closed, the result being an arrangement similar to that shown in FIG. 1. In some instances the filter member 33 of the vent arrangement 21 is applied after formation of the bag, rather than before.
According to the principles of the present invention, a pouch arrangement is provided which comprises: first and second opposed panel sections; a base gusset member; and, a gas filter arrangement oriented in one of the panel sections. The gusset member is preferably oriented between the panel sections, along ends thereof, to form a base by which the arrangement can be stood up during use. Since the arrangement can be readily stood up during filling, venting and use, it can be filled such that the solid material does not reach a level of position of the gas filter arrangement. In this manner interruption of operation of the gas filter arrangement, by material stored within the bag during filling, can be inhibited if desired. As will be seen from the detailed descriptions, the two panel arrangement facilitates this, by providing, through use of an upper transverse seal or seam, for a slanted side wall portion, which tends to lift and project the vent arrangement, when appropriately positioned, out of contact with solid material stored therein.
Preferably the arrangement is provided with closure means extending thereacross, provided with means for selective opening and reclosing of the pouch construction. A preferred such closure means is a rib and trough closure arrangement, such as sold under the trademark Ziploc(copyright) by Dow or ZipPak by Mini-Grip, Inc. In this manner, opening and reclosing the bag construction, for access to material therein, is facilitated. Further, it is facilitated in a manner which does not involve rolling or otherwise manipulating the material of the flexible bag in the region of the vent arrangement. Thus, potential failure in a manner similar to that of conventional systems is inhibited to advantage.
The preferred gas filter arrangement comprises a pore in one of the panel sections, with a filter arrangement such as porous filter member mounted thereover. Preferably the pore is relatively small in diameter, i.e. no greater than about 2.0 mm, more preferably no more than about 1.0 mm.
In preferred embodiments, the orientation of the gas filter arrangement pore, relative to the rib and trough closure arrangement, is selected to facilitate maintenance of the gas filter arrangement relatively clear of solid material when the material is poured into the bag construction during packaging and the bag construction is stood upright. In general, this is done by maintaining the pore arrangement within a preferred distance of the rib and trough closure system definable as a percentage of the distance between the rib and trough closure arrangement and the base gusset (or bag end adjacent the base gusset). Preferably, the pore is positioned within about 2% to about 30% of the distance between the rib and trough closure arrangement and the bottom gusset or panel end edges. More preferably, it is positioned within about 4 to 17% of that distance. In a typical preferred application it will be positioned about 2.5 to 5.0 cm from the rib and trough closure arrangement.
For the most preferred arrangements, the rib and trough closure arrangement is positioned a selected distance of at least 0.75 cm from an end of the bag arrangement. As a result, room is left over for a seal such as a heat seal across an open end of the bag, during packaging. Further, a tab arrangement is formed which can be cut or removed from the bag by the consumer, during use. Removal of this tab arrangement is facilitated, by selected positioning of tear notches in the bag arrangement.
The principles described herein also concern preferred methods for creating vented bag arrangements. One such preferred method comprises providing a continuous full web of panel sections of material; splitting the full web into first and second continuous half webs of panel section material; punching a pore into one of the two half webs of panel section material; forming a pouch arrangement from the first and second half webs, the pouch arrangement having opposed front and back panels, the front panel having the pore therein; and, applying a filter arrangement over the pore. Preferably the method includes positioning a base gusset between the front and back panels in a preferred orientation for operation in the completed arrangement. Most preferably, a rib and trough closure arrangement is also operably oriented between the front and back panels, during construction. In general, the method will also include steps of providing appropriate seals between adjoining members; and, trimming as necessary to provide the pouch.
The method described above lends itself well toward mass production techniques, utilizing continuous webs wherein a plurality of pores are positioned into one of the two half webs, and a plurality of pouch arrangements, each having one pore therein, are formed. In some applications a wide web can be provided in a manner forming two adjacent lines of pouches.
It will be understood that in alternate applications, the methods may involve forming the two panels from separate webs of material, rather than a single continuous web split into two half webs. In general, a decision about which method to utilize will depend in part upon availability of webs and the design of selected machinery for manufacture.
The pore may be created in a variety of manners. One convenient manner is through utilization of a punch or the like. The punch may be applied with sufficient force to create a small tear or rupture in the bag, of a size appropriate for forming a vent arrangement.
The methods described are advantageous, as the pore is applied in one of the panels before the two panel construction is formed. Thus, there is no risk of punching the pore completely through the bag or pouch arrangement.
The drawings constitute part of the specification and disclose details concerning preferred constructions and/or methods according to the invention. It will be understood that in some instances, relative material thicknesses or component sizes may be shown exaggerated, to facilitate an understanding of the invention.
FIG. 1 is a perspective view of a prior art bag construction involving a vent arrangement.
FIG. 2 is a perspective view of a panel arrangement depicted during a step of folding for the formation of an arrangement such as that shown in FIG. 1.
FIG. 3 is a front view of a flexible bag construction according to the present invention.
FIG. 4 is a perspective view of the arrangement shown in FIG. 3; FIG. 4 depicting the arrangement filled with material, for storage.
FIG. 5 is a cross-sectional view of FIG. 4 taken generally along line 5xe2x80x945 thereof.
FIG. 6 is an enlarged fragmentary view of a portion of FIG. 5.
FIG. 7 is an enlarged fragmentary view of a portion of FIG. 5.
FIG. 8 is a schematic flow chart of a preferred method of preparing a bag arrangement according to the present invention.
FIG. 9 is a schematic representation of certain of the steps illustrated in a preferred application of the method shown in the schematic flow chart of FIG. 8.
FIG. 10 is a schematic representation of a step of the preferred application of the schematic illustrated in FIG. 9.
FIG. 11 is a representation of a step of applying a filter arrangement to a pouch arrangement according to the present invention.
FIG. 12 is a schematic representation of a step of the preferred application of the schematic illustrated in FIG. 9.